Semiconductor device geometries have dramatically decreased in size since their introduction several decades ago. Modern semiconductor fabrication equipment routinely produces devices with 45 nm, 32 nm, and 28 nm feature sizes, and new equipment is being developed and implemented to make devices with even smaller geometries. The decreasing feature sizes result in structural features on the device having decreased spatial dimensions. The widths of gaps and trenches on the device narrow to a point where the aspect ratio of gap depth to its width becomes high enough to make it challenging to fill the gap with dielectric material. The depositing dielectric material is prone to clog at the top before the gap completely fills, producing a void or seam in the middle of the gap.
Over the years, many techniques have been developed to avoid having dielectric material clog the top of a gap, or to “heal” the void or seam that has been formed. One approach has been to start with highly flowable precursor materials that may be formed on a patterned substrate surface (e.g., SOG deposition techniques). These flowable precursors can flow into and fill very small substrate gaps without forming voids or weak seams.
In some applications the surfaces inside the substrate gaps may not be wettable by the flowable dielectric material. This tends to happen when the underlying material is deposited at high temperature, for example. Thus, there is a need for new deposition processes and materials to form dielectric materials on structured substrates, such that flowable materials can more easily penetrate gaps in the substrate surface. This and other needs are addressed in the present application.